How does this medication work? What will it do for me?

Flupenthixol belongs to the family of medications known as thioxanthenes. This medication is used in the treatment of schizophrenia. It is thought to work by affecting nerve pathways in certain areas of the brain to help correct certain chemical imbalances that cause the symptoms of schizophrenia.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are using this medication, speak to your doctor. Do not stop using this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to use this medication if their doctor has not prescribed it.

What form(s) does this medication come in?

2% Solution

Each mL contains flupenthixol decanoate 20 mg. Nonmedicinal ingredients: medium-chain triglycerides. Supplied as 2 mL ampoules, packages of 5, or as 10 mL vials.

10% Solution

Each mL contains flupenthixol decanoate 100 mg. Nonmedicinal ingredients: medium-chain triglycerides. Supplied as 2 mL vials.

How should I use this medication?

The recommended starting dose of flupenthixol tablets is 1 mg 3 times a day. The doctor may increase this dose every 2 or 3 days depending on how you are doing. The usual maintenance dose is 3 mg to 6 mg daily, taken in divided doses.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are using the medication without consulting your doctor.

Once you have reached a stable dose of flupenthixol tablets, your doctor may switch you to an injectable form of flupenthixol that stays in your system longer and makes it easier to remember to take your medication.

Flupenthixol tablets may be taken with food or on an empty stomach, however taking it with food or milk may help to reduce stomach upset.

It may take several weeks to feel the full benefit of this medication. Flupenthixol tablets must be taken every day to be effective. It is important that you keep taking the medication as prescribed by your doctor.

Your body will become accustomed to the medication over time. Do not stop taking this medication without talking to your doctor. If this medication is stopped suddenly, you may experience withdrawal symptoms such as nausea, vomiting, diarrhea, trouble sleeping, or loss of appetite. If you plan on stopping the medication, your doctor may want you to reduce the dose gradually to reduce the severity of withdrawal effects.

It is important that this medication be taken exactly as prescribed by your doctor. If you miss a dose of this medication, skip the missed dose and go back to your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

If you are using the flupenthixol injection and you miss an appointment to receive a dose, contact your doctor as soon as possible to reschedule your appointment.

Store this medication at room temperature and protect it from light.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not use this medication if you:

  • are allergic to flupenthixol or any ingredients of this medication
  • are allergic to other thioxanthines (e.g., thiothixine)
  • are intoxicated with alcohol or other medications (such as hypnotics, other opioids like codeine or morphine, or psychotropic medications for mental health conditions)
  • have brain damage
  • have liver damage
  • have serious heart disease, brain disease, or kidney disease

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • changes in menstrual periods
  • constipation
  • decreased interest in sexual activity
  • decreased sexual ability
  • dizziness
  • dry mouth
  • fatigue
  • increased production of saliva
  • increased sensitivity of the skin to sunlight
  • increased sweating
  • stuffy nose
  • swelling of breasts (in men and women)
  • unusual secretion of milk
  • weight changes

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • blurred vision or other eye problems
  • circular eye movement
  • decreased blood pressure (fainting, dizziness, lightheadedness)
  • difficult urination
  • fast, pounding heartbeat
  • mask-like face
  • muscle spasms, especially of the neck and back
  • new or worsening constipation
  • severe restlessness or need to keep moving
  • shuffling walk
  • signs of liver damage (e.g., yellowing of skin or whites of eyes, abdominal pain, loss of appetite, dark urine, light-coloured stools, tiredness, or weakness)
  • skin rash
  • stiffness of arms and legs
  • symptoms of a blood clot in the arm or leg (tenderness, pain, swelling, warmth, or redness in the arm or leg) or lungs (difficulty breathing, sharp chest pain that is worse when breathing in, coughing, coughing up blood, sweating, or passing out)
  • trembling and shaking of fingers and hands
  • uncontrolled body movements (e.g., twisting movements, chewing movements, puffing cheeks, lip smacking or puckering)

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • difficulty breathing
  • increased sweating
  • long-lasting (more than 4 hours) and painful erection
  • loss of bladder control
  • seizures
  • severe dizziness
  • signs of a heart attack (e.g., chest pain or pressure, pain extending through shoulder and arm, nausea and vomiting, sweating)
  • signs of a stroke (e.g., headache, loss of coordination, slurred speech, weakness, numbness, or unexplained pain in the arm or leg)
  • signs of neuroleptic malignant syndrome (e.g., high fever, muscle stiffness, confusion or loss of consciousness, sweating, racing or irregular heartbeat, or fainting)
  • unusual tiredness
Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Abnormal heart rhythms: This medication can cause abnormal heart rhythms. Certain medications (e.g., sotalol, quinidine, thioridazine, chlorpromazine, droperidol, pimozide, , moxifloxacin, mefloquine, pentamidine, arsenic trioxide, , probucol, tacrolimus) can increase the risk of a type of abnormal heart rhythm called QT prolongation, and should not be used in combination with flupenthixol. You are more at risk for this type of abnormal heart rhythm and its complications if you:

  • are female
  • are older than 65 years of age
  • have a family history of sudden cardiac death
  • have a history of heart disease or abnormal heart rhythms
  • have a slow heart rate
  • have congenital prolongation of the QT interval
  • have diabetes
  • have had a stroke
  • have low potassium, magnesium, or calcium levels
  • have nutritional deficiencies

Blood counts: This medication can decrease the number of neutrophils (a type of white blood cell that helps fight infection), red blood cells (which carry oxygen), and platelets (which help your blood to clot). Your doctor will do blood tests to monitor this. If you notice any signs of infection (e.g., fever, chills, or sore throat) or unusual bleeding or bruising, contact your doctor immediately.

Blood sugar: Flupenthixol may cause an increase in blood sugar levels (may cause a loss of blood glucose control) and glucose tolerance may change. This may happen to people who have never had high blood glucose levels. People with diabetes may find it necessary to monitor their blood sugar more frequently while using this medication.

If you have diabetes or are at risk for developing diabetes, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Dementia: Adults with dementia appear to be at a greater risk of sudden death when they are taking flupenthixol. This appears to happen more often in seniors with dementia. If you have dementia, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Drowsiness/reduced alertness: This medication may cause drowsiness. Do not drive, operate machinery, or perform other potentially hazardous tasks until you have determined how this medication affects you.

Glaucoma: This medication may make glaucoma worse. If you have glaucoma, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver function: Liver disease or reduced liver function may cause this medication to build up in the body, causing side effects. If you have liver disease or decreased liver function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Flupenthixol may also cause decreased liver function or make liver problems worse. If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

Movement disorders: The use of flupenthixol has been associated with a potentially irreversible movement disorder called tardive dyskinesia (TD). This syndrome involves the involuntary movements of facial muscles and the tongue. The risk of a person developing this syndrome is usually but not always linked to treatment duration and the total amount of antipsychotic medications taken.

If you develop signs and symptoms of TD during treatment with flupenthixol, including sticking the tongue out, smacking the lips, pursing or puckering of lips, and blinking eyes rapidly, contact your doctor as soon as possible.

Neuroleptic malignant syndrome (NMS): Flupenthixol, like other antipsychotic medications, can cause a potentially fatal syndrome known as neuroleptic malignant syndrome (NMS). If you notice the symptoms of NMS such as high fever, muscle stiffness, confusion or loss of consciousness, sweating, racing or irregular heartbeat, or fainting, get immediate medical attention.

Parkinson's disease: This medication may make symptoms of Parkinson's disease worse. If you have Parkinson's disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Prolonged erection (priapism): If an erection lasts longer than 4 hours (a rare occurrence), seek immediate medical assistance. If this condition is not treated quickly, tissue damage and permanent loss of the ability to have an erection could result.

Seizures: Flupenthixol may make pre-existing seizure disorders worse. If you have a seizure disorder, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Stopping the medication: If this medication needs to be stopped, it should be done gradually, under the supervision of your doctor. If you suddenly stop taking this medication, you may experience symptoms of withdrawal.

Take the medication exactly as prescribed by your doctor, and do not stop taking the medication without checking with your doctor first.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately. Newborn babies who have been exposed to this medication in the last 3 months of pregnancy have experienced withdrawal symptoms after birth.

Breast-feeding: This medication passes into breast milk. If you are a breast-feeding mother and are taking flupenthixol, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children.

Seniors: Seniors are at an increased risk of experiencing severe side effects of flupenthixol due to decreased kidney, liver, and heart function. Discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

What other drugs could interact with this medication?

There may be an interaction between flupenthixol and any of the following:

  • aclidinium
  • alcohol
  • alfuzosin
  • amantadine
  • amiodarone
  • amphetamines (e.g., dextroamphetamine, lisdexamphetamine)
  • anagrelide
  • antihistamines (e.g,. cetirizine, doxylamine, diphenhydramine, hydroxyzine, loratadine)
  • anti-Parkinsons medications (e.g., amantadine, apomorphine, bromocriptine, levodopa, pramipexole, ropinirole)
  • antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine, risperidone)
  • antiseizure medications (e.g., clobazam, ethosuximide, felbamate, levetiracetam, phenobarbital, phenytoin, primidone, topiramate, valproic acid, zonisamide)
  • apomorphine
  • aripiprazole
  • atropine
  • azelastine
  • "azole" antifungals (e.g., itraconazole, ketoconazole, voriconazole)
  • baclofen
  • barbiturates (e.g., butalbital, pentobarbital, phenobarbital)
  • belladonna
  • benzodiazepines (e.g., alprazolam, diazepam, lorazepam)
  • benztropine
  • bosutinib
  • brimonidine
  • bromocriptine
  • buprenorphine
  • buspirone
  • cannabis
  • chloral hydrate
  • chloroquine
  • cisapride
  • cyclobenzaprine
  • desvenlafaxine
  • dextromethorphan
  • disopyramide
  • domperidone
  • donepezil
  • doxepin
  • dronedarone
  • efavirenz
  • epinephrine
  • ergot alkaloids (e.g., ergotamine, dihydroergotamine)
  • famotidine
  • fingolimod
  • flavoxate
  • flecainide
  • formoterol
  • gabapentin
  • galantamine
  • goserelin
  • guanethidine
  • glycopyrrolate
  • indapamide
  • ipratropium
  • kava kava
  • ketotifen
  • levodopa
  • lithium
  • lopinavir
  • macrolide antibiotics (e.g., azithromycin, clarithromycin, erythromycin)
  • magnesium sulfate
  • maprotiline
  • mefloquine
  • methadone
  • methylphenidate
  • metoclopramide
  • mifepristone
  • mirtazapine
  • monoamine oxidase inhibitors (MAOIs; e.g., moclobemide, rasagiline, selegiline, tranylcypromine)
  • muscle relaxants (e.g., cyclobenzaprine, methocarbamol, orphenadrine)
  • nabilone
  • narcotic pain relievers (e.g., codeine, fentanyl, morphine, oxycodone)
  • octreotide
  • olopatadine
  • orphenadrine
  • oxybutynin
  • pentamidine
  • perampanel
  • pimozide
  • potassium chloride (potassium supplements)
  • procainamide
  • promethazine
  • propafenone
  • romidepsin
  • quinidine
  • quinine
  • quinolone antibiotics (e.g., levofloxacin, norfloxacin, moxifloxacin)
  • ritonavir
  • rivastigmine
  • romidepsin
  • St. John's wort
  • saquinavir
  • scopolamine
  • selective serotonin reuptake inhibitors (SSRIs; e.g., paroxetine, fluoxetine, citalopram)
  • serotonin antagonists (anti-emetic medications; e.g., granisetron, ondansetron)
  • solifenacin
  • sotalol
  • sulfamethoxazole
  • tacrolimus
  • tamoxifen
  • tapentadol
  • tetrabenazine
  • thalidomide
  • thiazide diuretics (water pills; e.g., hydrochlorothiazide, indapamide, metolazone)
  • thioridazine
  • tiotropium
  • tolterodine
  • tramadol
  • trazodone
  • trimethoprim
  • tricyclic antidepressants (e.g., amitriptyline, clomipramine, desipramine, trimipramine)
  • "triptan" migraine medications (e.g., eletriptan, sumatriptan)
  • tryptophan
  • tyrosine kinase inhibitors (e.g., dasatinib, imatinib, nilotinib, sunitinib)
  • umeclidinium
  • vardenafil
  • venlafaxine
  • zolpidem
  • zopiclone

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.